As is known, various mechanics are utilized in connection with blasting, as, for example, at a coal mine site, and particularly in connection with what is termed pre-split blasting. In such instance, and typically, an inflatable air bag is utilized in the drilled hole for retaining fill at a preselected level. The preceding involves considerable cost, in view of the usual number of blasting sites and, as well, oftentimes fails to effectively maintain the desired seal with the wall of the blasting hole.